1. Cambridge Studies in Advanced Mathematics;Benson, D. J.,1991
2. Combinatorial models for real configuration spaces and 𝐸_{𝑛}-operads;Berger, Clemens,1997
3. BergerFresse Berger, C. and Fresse, B., Combinatorial operad actions on cochains. Preprint available at http://front.math.ucdavis.edu/math.AT/0109158
4. Homotopy-everything 𝐻-spaces;Boardman, J. M.;Bull. Amer. Math. Soc.,1968
5. Deligne Deligne, P., Letter to Stasheff et al. May 17, 1993.